Opened up my Indigo once to reccy some wobbly pots.
* Red = a floating/hovering PCB that piggy backs onto the back of the main PCB board.
* Green = the mainboard (which houses the pots)
* Blue = the pitch/mod wheels
There are several ribbon cables in the virus connecting the modular parts, including the keybed, PSU, the PCBs, fascia, and the mod/pitch wheels. In fact you can clearly see one of the main grey ribbon cables going into the Mod/pitch wheel PCB there on the pic, and there is a separate local plug with the coloured wires too. Any of these may have become loose, so it would be worth checking them out like Mono suggests before you bundle it all up and send it anywhere.
Contact these guys:
http://www.synthesizerservice.de/index.php?lang=en
... and ask them for details on how to open up your Virus. They'll send you photos with brief descriptions. (That's what they did for me, anyhow).
They are the hardware branch for Access Music.
Disclaimer: If your TI is still within your warranty period, opening up the Virus will void it. If it's outside the warranty period you have nothing to lose, and it's not like it's particularly risky anyway. Just take the usual care with regards to grounding (to avoid static, which can harm electronics), and electric shock (in other words don't leave your Virus plugged in!)
"This bag of peanuts may contain peanuts", etc. etc.